Method of manufacturing seamless wrought-iron annealing boxes



T. LAMMINE METHOD OF MANUFACTURING SEAMLESS WROUGHT IRON ANNE'ALING BOXES April 5, 1927.

Filed 001:.

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Jh'z arn. eg I Patented Apr." 5, 192 7.

1 .UNITED sTArEs -PA 'EN OFFICE- rrmonon or oonoenn-rrumnm, eznmmr. warrior or mriurscrume snAmLEss wnoue'nr-Iaon mums noxns.

" Applicaflqn filed October 25, 1924, semi nor-145,886, and in Germany ltovember a, 1923.-

In connection with the manufacture of cylindrical annealing boxes with an outwardly offset reinforced margin in one piece without welded seems, it has been proposed to form the body of the work-piece vfrom a block of. metal by pressing-and. drawing. However, .in carrying out this process inpractice, especially if it was thequesactual tionzo making annealing boxes of lar e diameters as are mostly used, certain gard to the widening of the rolled block and bottom.

It is the objectof the present. invention 'to provide an improved method'forproducing an annealing boxoi the seamless type which mouth portion. I

will bestrong and durable, the invention residing in the method and steps hereinafter described in detail, of drawing out the bodly;

- of the box from a sheet metal blank throug a succession of die operations, and supplementing these: with .upsetting operations whereby a seamless box is produced presenting a thickened outwardly oifset rimor In orderto obtain the desired otfset shape of'the marginal portion the work-piece is treated .as follows. Upon the cyhndrical shell of-the work-piece having been reduced to a certain diameter by drawing it through the drawing die, the work-piece is no longer drawn entirely through the die in the suc.

ceeding steps of. the drawing process, but

the drawing operation is interrupted Before the marginal portion enters through the die so that the oflset marginal portion produced thereby does not only retain, its previous larger diameter, but that also the effect of the upsetting taking place before the drawing out and reducing, is retained. In this I, way the marginal portions may .be given a thickness of material which ficient for certain purposes. 1

In order to increase even more the wallthickness of the offset margin remaining u'ndrawn during the-last steps of the drawing process, the margin is subjected during the drawing-process or between the several steps or after] the drawing process has been terminated, to a special upsetting operation re- V ducing the diameter of the margin without,

however, drawing it out.

In order to allow of the invention to be more readily understood it will now be de-f continued through severa' severat drawing operations or is already suf-.

scribed with reference to. the accompanying drawing in which:

Figs. 1 to 3 diagrammatically. illustrate the course of the method in three different steps, the'work-piece being shown in longi tudmal axial sections.

Fig. 4 illustrates a special mode of the the sheet plate 1 which is indicated by dot and dash linesin I Fig. 1. This plate is first drawn by means of a drawing stamp 3 through a draw die 2 having a suitable diameter so as toproduce a short cylinder 5 provided with a bottom 4.. After, repeatlng this operation several times-by using dies and stamps of successively smaller diameters, the next st 'e of the drawing process, as shown. in Fig. 2, consists 1 means of the 'stamp 7 through the hole of the in drawing. the work-piece by die 6,-to such an extent only that the marginal portion 8 remains above'the die unreduced and undrawn. The drawin process is then steps during which the lower cylinder portion ofthe work-piece is further reduced andelongated as at 12in Fig. 5. Preferably between the subsequently the .ofiset marginal portion. is subjected toso I an upsetting operation, for instance, by

means of two or more jaws 9 moved together .in lateral direction asindicated by the opposed small arrows in Fig. 3 thereby efl'ectmg a reduction of. the diameter of the oil'- set marginal portion Without elongating it,

thus increasing its wall-thickness correspondingly.

As shown. in Fig. 4, the upsetting of the offset marginal portion may also be prodn'ced by placing it in an upsetting die '10, the hole of which has .a tapering portion, and compressing it mainly in its longitudinal direction by means of a axiallyagainst the top edge of the'margin. After finishing the upsetting operations, the exact or approximately exact final shape shown in Fig. 5, may be given to the marginal portion by pressing'it by means of a profile die and profile stamp.

The suspension eyes or lugsused in some cases may either be welded to the cylindrical ortion of the offset margin or they may .be ormed from the marginal portion itself stamp 11 pressed by cutting away the superfluous parts of the margin which is then made of a suitable length.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. The method of manufacturing a seamless wrought-iron annealing box with an outwardly offset thickened and reinforced mouth portion of greater internal and external diameter than the body thereof, consisting in axially pressing a portion of a blank sheet. of metal through a die so as to form a cup-shaped body and'so as to leave a predetermined marginal portion of the blank undrawn, drawing out the drawn cupshaped body by progressive stages so as to elongate while reducing in diameter'and wall thickness such cup-shaped body, thereby leaving unimpaired about the mouth of the finished cup-shaped body a marginal portion of greater internal and external diameter than the body and of the original wall thickness of the sheet, and then by inward lateral compression diametrically contracting said marginal portion, without reduction of its wall thickness, from the diameter at which it is left at the cessation of the body-forming operation to a smaller diameter in which it remains of greater internal and external diameter than the drawn bod fl The method of manufacturing a seamless wrought-iron annealing box with an outwardly offset thickened and reinforced marginal portion, consisting in axially pressing a portion of a blank sheet of metal through a die so as to form a cup-shaped body and so as to leave a predetermined marginal portion of the blank undrawn, elongating the body by progressive stages so as to draw out and reduce in diameter and wall thickness such cup-shaped body, thereby leaving unimpaired about the mouth of the finished cup-shaped body a marginal portion of greater internal and external diameter than the body and of the original wall thickness of the sheet, and then by axial compression reducing the depth of said marginal portion and by lateral compression contracting the same without reduction of wall thickness to an internal and external diameter less than its original diameter but greater than that of the drawn body.

3. The method of manufacturing a seamless wrought-iron annealing box with an outwardly offset thickened and reinforced marginal mouth portion, consisting in axially pressing a portion of a blank sheet of metal through a die so as to form a cupshaped body and so as to leave a marginal portion of the sheet of greater internal and external diameter than the body about the mouth of the body, drawing out the cup-.

shaped body so formed so as to elongate and reduce its thickness and diameter while leaving unimpaired the marginal portion of original wall thickness of the sheet, and then radially and axially contracting and reducing the depth of said marginal portion to a depth less than its original depth and to a diameter less than its original diameter but to a diameter greater internally and externally than that of the drawn body, so as to produce a mouth portion of greater thickness than the body and of uniform diameter and concentric with the body at its point of juncture therewith, and whereby the material at such point of juncture is simultaneously shaped to present a reinforced stepped formation on the inside and a smooth flaring contour on the outside of the base of the offset mouth portion.

In testimony whereof I have signed my name to this specification.

THEODOR LAMMINE. 

